There are systems, such as synchronous motors and generators, which supply electrical current to a rotor winding by way of slip rings. The current is typically applied to the slip rings via brushes mounted on a fixed conducting ring. Ordinarily, the slip rings in such systems are at low voltage. Some high voltage systems also employ slip rings for such purposes as power transfer. See, in this regard, U.S. Pat. No. 3,471,708 to Rauhut for a rotary transformer for coupling multiphase systems having a small frequency difference.
The carbon brushes typically utilized in such motors and generators wear with use over time. Dust from the worn brushes can accumulate and contaminate insulation surfaces, thereby causing undesirable effects. Moreover, operative elements in such motors and generators can become quite hot due, e.g., to electrical losses and mechanical friction.
What is needed, and an object of the present invention, is a high voltage electrical system which provides cleaning and cooling to enhance overall operation.
An electrical current collector system comprises an electrically conductive slip ring mounted to a rotatable shaft, as well as a fixed conducting ring assembly having slip ring-contacting members mounted thereon. The slip ring and fixed conducting ring assembly are mounted to have an annular gap formed therebetween. A slip ring support assembly comprising plural post insulators spaced radially about the rotatable shaft attaches the conductive slip ring to the rotatable shaft. The slip ring and fixed conducting ring assembly are at least partially enclosed in a compartment, to which a source applies a cooling/cleaning fluid.
In accordance with the structure and method of the invention, the source directs the fluid over at least some of the post insulators for cleaning of the post insulators. Then the fluid travels through the gap to perform at least one of cooling and cleaning of an interface of the slip ring and the slip ring-contacting members.
The fixed conducting ring assembly forms an envelope having a conductive ring channel in which the slip ring-contacting members are mounted. After passing through the gap, the cooling/cleaning fluid enters into the conductive ring channel. The conductive ring channel directs the fluid in at least a partially semicircular path to an exhaust duct.
In one example deployment, the fixed conducting ring assembly is utilized in a rotating transformer system wherein the electrical current collector system applies current to a rotor assembly having rotor windings which rotates about the rotatable shaft, and wherein a stator has stator windings, and a motor is provided for rotating the rotor assembly.